From: rudi.j.blom@gmail.com (Rudi Blom)
Subject: [TUHS] communication files: interprocess IO before pipes
Date: Tue, 7 Mar 2017 11:16:56 +0700 [thread overview]
Message-ID: <CAMYpm87_dNaDL4kqjzxroffigpoS9L4+yZcaMsCrfKiHr0YgJQ@mail.gmail.com> (raw)
On SCO UNIX 3.2V4 pipes where simulated as follows
int fd[2]
struct strfdinsert ins;
/*
* First open the stream clone device "/dev/spx" twice,
* obtaining the two file descriptors.
*/
if ( (fd[0] = open(SPX_DEVICE, O_RDWR)) < 0)
{
gen_trace(gtr_flag, "-gen_pipe(): -open(fd[0]): %s\n", strerror(errno));
break;
}
if ( (fd[1] = open(SPX_DEVICE, O_RDWR)) < 0)
{
gen_trace(gtr_flag, ">gen_pipe(): -open(fd[1]): %s\n", strerror(errno));
close(fd[0]);
break;
}
/*
* Now link these two streams together with an
* I_FDINSERT ioctl.
*/
ins.ctlbuf.buf = (char *) &pointer; /* no ctl info, just the ptr */
ins.ctlbuf.maxlen = sizeof(queue_t *);
ins.ctlbuf.len = sizeof(queue_t *);
ins.databuf.buf = (char *) 0; /* no data to send */
ins.databuf.len = -1; /* magic: must be -1, not 0, for stream pipe */
ins.databuf.maxlen = 0;
ins.fildes = fd[1]; /* the fd to connect with fd[0] */
ins.flags = 0; /* nonpriority message */
ins.offset = 0; /* offset of pointer in control buffer */
if (ioctl(fd[0], I_FDINSERT, (char * ) &ins) < 0)
{
gen_trace(gtr_flag, ">gen_pipe(): -ioctl(I_FDINSERT): %s\n", strerror(errno));
close(fd[0]);
close(fd[1]);
break;
}
/*
* reset close_on_exec flag
*/
gen_trace(gtr_flag, ">gen_pipe(): +fcntl()\n");
if ((rc = fcntl(fd[0], F_SETFD, 0)) == -1)
gen_trace(gtr_flag, ">gen_pipe(): -fcntl(fd0, close_on_exec): %s\n",
strerror(errno));
if ((rc = fcntl(fd[1], F_SETFD, 0)) == -1)
gen_trace(gtr_flag, ">gen_pipe(): -fcntl(fd1, close_on_exec): %s\n",
strerror(errno));
rc = 0;
break;
reply other threads:[~2017-03-07 4:16 UTC|newest]
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